Synovial fluid level of aggrecan ARGS fragments is a more sensitive marker of joint disease than glycosaminoglycan or aggrecan levels: A cross-sectional study
Larrson S et al. – In this cross-sectional study, comparing knee of healthy persons with acute inflammatory arthritis, acute knee injury, chronic knee injury and knee osteoarthritis, the SF levels of the aggrecan ARGS neoepitope were quantified with a modified sandwich ELISA and was compared with aggrecan assays not specific for this neoepitope. Data show that ARGS neoepitope concns in SF differ between these groups and this method is more sensitive measure of joint disease than previously used aggrecan or sGAG assays.Methods- A quantitative immunoassay of aggrecan ARGS neoepitope fragments in human SF to determine if this cleavage-site specific method better identifies joint pathology than previously available less specific aggrecan assays
- SF from 26 knee healthy persons and 269 pts were analyzed
- Patient groups: acute inflammatory arthritis, acute knee injury, chronic knee injury and knee OA
- Aggrecan ARGS fragments were assayed by ELISA using the monoclonal antibody OA-1
- Total aggrecan content was analyzed by an ELISA using the monoclonal antibody 1-F21, and sulfated glycosaminoglycan by Alcian blue precipitation
Results- Aggrecan ARGS fragment concns in all groups differed from the reference group
- Acute inflammatory arthritis group had the highest median level; >177-fold vs reference group
- Median levels were: reference 0.5, acute inflammatory arthritis 88.5, acute knee injury 53.9, chronic knee injury 0.5 and OA 4.6
- In contrast, aggrecan and sulfated glycosaminoglycan concns varied much less between groups
- Only acute inflammatory arthritis and acute knee injury showed 2-fold increase in median levels vs reference
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